Starting and operating circuits for gaseous electric discharge devices



@cih 6, 193% H. EWEST ET AL 2,56,fi58

STARTING AND OPERATING CIRCUITS FOR GASEOUS ELECTRIC DISCHARGE DEVICESFiled Feb. 20, 1936 INVENTORS H a n s Ewes'b ATT RNEY Patented Oct. 6,1936 UNITED STATES STARTING AND OPERATING CIRCUITS FOR GASEOUS ELECTRICDISCHARGE DE- VICES Hans Ewest, Berlin-Lichterfelde-Ost, and MartinReger, Berlin-Charlottenburg, Germany, assignors to General ElectricCompany, a-corporation of New York Application February 20, 1936, SerialNo. 64,962

InG

ermany February 28, 1935 1Claim. (01.1'76-124) container I having. maindischarge supporting The present invention relates to starting andoperating circuits for gaseous electric discharge devices and moreparticularly the invention relates to such circuits comprising acapacitance and an auto-inductance connected in series with the deviceacross the terminals of an alternating current source which capacitanceand inductance are so dimensioned with respect to each other that aresonance voltage is generated thereby. The resonance voltage efiects aquick ionization of the discharge path to facilitate the starting of thedischarge and is particularly efficacious when auxiliary, startingelectrodes are mounted in the device.

We have observed that when the gaseous elec tric discharge device in acircuit of the above type comprises a main discharge supportingelectrode having a body of highly electron emissive material associatedtherewith this material is deleteriously' affected by the sudden currentsurges at said main electrode resulting from the discharge of thecapacitance. The useful life of the main electrode and the dischargedevice is thus reduced. The object of the present invention is toprovide a starting and operating circuit of the resonant type for agaseous electric discharge vdevice in which detrimental current surgesat the main discharge supporting electrodes are avoided to increase theuseful life of the device. Still further objects and advantagesattaching to the circuit and to its use and operation will be apparentto those skilled in the art irom the follow- I ing particulardescription.

.The invention attains its objects by connecting in parallel with thegaseous electric discharge device two choke coils and a capacitanceconnected in series with each other with the capacitance connectedbetween the choke coils. The gaseous electric discharge device isprovided with two In the drawing accompanying and forming part of thisspecification an embodiment of the invention is shown schematically.

Referring to the 'drawing'the gaseous electric 55, discharge devicecomprises an elongated tubular auxiliary electrodes each mountedadjacent acircuit avoids detrimental current surges at the electrodes 2and 3 sealed therein at each end thereof. Said electrodes 2 and 3comprise an electron emitting material, such as an alkaline earth oxide,and are heated to an electron emitting, discharge supporting temperaturedurin the operation of the device by the current flow therethrough andthe voltage drop thereat. Auxiliary, starting electrodes i5 and 16 aresealed into said container I adjacent saidmain electrodes 2 and 3,respectively. Said container I has a gaseous atmosphere thereincomprising a gas, a metal vapor, or a mixture of gas and metal vapor,such as a mixture of argon and mercury vapor. The pressure of thegaseous atmosphere is in the range of a few mm. to hundreds of mm., whendesired. The main electrodes 2 and 3 are connected to the terminals 8and 5, respectively, of an alternating current source by the currentleads 6 and 4, respectively. A ballast resistance 1 is connected intothe current lead 6.

The electrodes 2 and 3 are bridged by the current lead 9 which has twochoke coils H and i2 connected therein and a condenser l0 connected inseries with and between said choke coils ii and I2. The auxiliaryelectrodes l5 and it are connected to the lead '9 between the choke coilii and the condenser Ill and between the choke coil l2 and the condenserIll, respectively, by the leads i3 and M, respectively. The condenser l0and the choke coils ii and i2 are of such size with respect to eachother that at the frequency of the alternating current source resonancevoltages occur at'said choke coils ii and i2 and at said condenser Ml.

' When potential is applied to the above described circuit the resonancevoltage at the choke coil ii is impressed on the auxiliary electrode 15and initiates a gaseous electric discharge between said auxiliaryelectrode I5 and the main electrode 2. Similarly the resonance voltageat the choke coil i2 is applied to the auxiliary electrode l6 andinitiates a gaseous electric discharge between the auxiliary electrodel6 and main electrode a. Simultaneously the resonance voltage at'thecondenser Ill is impressed on the two auxiliary electrodes I5 and i6 toinitiate a gaseous electric discharge between said auxiliary electrodesl5 and I6. These three gaseous electric discharges together extend alongthe entire length of the main discharge path between said mainelectrodes 2 and 3. The gas throughout the length of the main dischargepath is quickly ionized by the auxiliary discharges and the maindischarge between said electrodes 2 and 3 is quickly started.

The quick starting of the main discharge is facilitated by the abovedescribed circuit not only when potential is first applied to thecircuit but also on each half cycle of the alternating current source.

While we have shown and described and have pointed out in the annexedclaims certain novel features of the invention, it will be understoodthat various omissions, substitutions and changes in the forms anddetails of the circuit illustrated and in its use and operation may bemade by those skilled in the art without departing from the broad spiritand scope of the invention, for example, a choke coil or a condenser isused in place of,the ohmic resistance 1, when. desired, and in this casethe choke coils II and I2 or the condenser ID are reduced in size whenthe suggested substitution results in an increased impedance in theseries resistance. When desired, a plurality of condensers are connectedin series between the choke coils II and I2.

What we claim as new and desire to secure by Letters Patent of theUnited States, is:-

A starting and operating circuit for a gaseous electric discharge devicecomprising in combination, an alternating current source, a gaseouselectric discharge device connected across the terminals of said currentsource, and having an auxiliary electrode mounted adjacent each of themain electrodes sealed therein, an impedance connected in series withsaid discharge device and a resonance circuit connected in parallel withsaid gaseous electric discharge device, said resonance circuitcomprising two inductances and a capacitance connected in series,- saidcapacitance being connected between said inductances, the auxiliaryelectrodes of said device being connected into said resonance circuit onopposite sides of said capacitance to facilitate the starting of themain discharge in said gaseous electric discharge device.

HANS 'EWEST. MARTIN REGER.

